The present invention relates to closures for bottles and other containers and is particularly directed to a tamper-evident closure which will provide the user with a clear indication that the container has previously been opened. Many different closure caps have been used to seal bottles and other containers. One persistent problem with many of these closures is that they do not provide protection against unauthorized tampering with the contents of the container.
More particularly, the construction of conventional caps is such that they may be removed from the container, a contaminant injected into the contents and then the cap can be resealed so that there is no evidence that the container has been tampered with. Various container closures have been suggested to address this problem.
For example, Sharp U.S. Pat. Nos. 1,796,728 and 1,796,729 disclose caps for bottles constructed to have detents formed on the upper beads of the bottles. A thin metal cap is applied to the bottle so that the periphery of the cap assumes the contour of the detent. Subsequently, when the cap is rotated, the detents in the cap are forced outwardly so that the cap assumes a planar appearance. This is intended to provide an indication that the cap has been removed. However, the cap may be replaced on the container and, if pressure is applied about the periphery of the cap, the cap may again be given an irregular configuration so that an inattentive user may not realize that the cap had been previously opened.
Another deformable, but resealable, cap is shown in Amabili U.S. Pat. No. 4,055,266. This patent discloses a twist-off cap which includes one or more flanges disposed above its bottom edge. These flanges are turned under a bead on the bottle and are provided with a series of vertical lines of weakening. When the cap is removed, the flanges are distorted outwardly and either rupture or separate at the vertical lines of weakening to provide a visual indication that the cap has been removed. Again, however, the cap shown in this patent can be used to reseal the container and an inattentive user may not be alerted to the fact that the container had previously been opened.
A different form of tamper-evident closure is disclosed in Herr U.S. Pat. No. 4,595,110. This patent discloses a threaded cap including a security ring or band joined to the upper portion of the cap along a line of weakening. When the cap is unthreaded from the bottle, the band separates along the line of weakening and remains on the bottle. To insure that the band does not come off under the worst tolerance conditions, the band includes a plurality of inwardly-extending, thin plastic tabs which engage the bottle.